SpectraFlex center to define the future of wireless

Wireless technology is racing toward ubiquity. Innovative new commercial, scientific and military applications are emerging at an almost unimaginable rate.

“There are thousands of new satellites going into orbit, autonomous vehicles are becoming a reality and we all want high-speed connectivity for our devices everywhere we go,” said Sayfe Kiaei, a professor of electrical engineering in the Ira A. Fulton Schools of Engineering at Arizona State University.

At the same time, the electromagnetic spectrum that serves as the medium for this explosion of data transfer is a limited resource. Challenges related to sufficient access, signal interference and poor latency or performance delays are sources of growing global concern.

“And while the United States has been a leader in the development of wireless technologies since World War II, there is now a lot of international competition for dominance in this arena. This is why 5G mobile networks have been such a hot topic in recent years,” Kiaei said. “As a result, the National Science Foundation has called for the creation of a new national center for research, innovation and workforce training to maintain our edge in wireless spectrum use and management.”

That call went out in August 2020, when leading scientists and engineers at U.S. universities were asked to develop detailed proposals for the structure and operation of the new $25 million facility — currently known by its working name, Spectrum Innovation Initiative Center, or SII-Center. In rapid response, multi-institutional teams began forming to leverage complementary expertise as they developed their plans.

Kiaei leads one of these teams, comprised of more than two dozen colleagues at Arizona State University; Cornell University; Florida Atlantic University; Florida International University; Rice University; the University of California, Los Angeles; the University of Michigan and Yale University.

“Our comprehensive plan highlights a flexible approach to the spectrum,” Kiaei said. “We need very adaptive architecture and systems to permit rapid advances in wireless functionality for everything from personal communication and weather sensing telemetry to intelligent transportation networks and more. Reflecting that focus on flexibility, our center name is SpectraFlex.”

The SpectraFlex proposal envisions the new national center organized by discrete but mutually supportive technology research and development thrusts. These areas include terahertz sensors and circuits, digital signal processing systems and artificial intelligence, and very large-scale integration of semiconductor and telecommunication technologies.

The faculty members working together in each thrust will pool their talent and resources to tackle a variety of challenges. One example is equipment reconfigurability to enable operation in either a sensing mode or a communication mode, while another focus is getting electronics to operate across a wide range of frequencies without degrading performance.

“The current approach to building good radio technology is tuning everything to a particular operating point. We optimize something for a very specific use,” said Alyssa Apsel, a professor of electrical engineering and director of the School of Electrical and Computer Engineering at Cornell University, as well as the leader of the radio-frequency integrated circuit and transceiver thrust at SpectraFlex.

“Of course, it is possible to make things that are flexible, but you almost always sacrifice performance,” Apsel said, pointing as an example to the difference between an application-specific integrated circuit and a general-purpose computer.

“The integrated circuit does one thing very efficiently, while the general computer does many things pretty well — but by consuming a lot of power and taking up a lot more space,” she said. “The same is true for radio technology. So, we intend to research and develop new systems that are not forced to trade performance for flexibility.”

More broadly than specific technical challenges, the SpectraFlex proposal aims to catalyze a dramatic change to the current collective mindset about the electromagnetic spectrum. The focus should be not just popular issues like 5G or the Internet of Things, but preparing for the wireless world we need in place 30 years from now.

“Think about how wireless data has been totally redefined during just the past five years. It’s a fundamental part of our lives from agriculture to logistics to education to defense,” said John Volakis, a professor of electrical engineering and dean of the College of Engineering & Computing at Florida International University as well as the leader of the multiple-input and multiple-output antennas thrust at SpectraFlex. “Consequently, the ways we use the spectrum have outpaced the technology we have in place. By that, I mean we have so many new applications, but the background systems supporting them haven’t changed much.”

Volakis says this is because we typically develop technologies in an evolutionary manner. Changes are iterative and rooted in what already exists.

“But we now need a revolutionary change,” he said, “and a center like SpectraFlex can take on the risk of developing a new paradigm and open new pathways to transporting wireless data.”

To help open those pathways, Kiaei says that the SpectraFlex proposal team has been actively engaging with leaders of the information technology and communications industries to identify key collaboration opportunities.

“At a workshop earlier this spring, we were discussing the new center with more than 80 representatives from a wide range of enterprises,” he said. “And those discussions include identifying workforce development needs. It’s vital that ASU and other universities train tens of thousands of new scientists and engineers to help push the new technology forward and make the promise of SpectraFlex a reality.”

Final proposals for the new wireless spectrum center are due for submission to the National Science Foundation by the end of April, and selection of the winning plan is expected this summer.